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Biomedical subjects

M Korobaeff

Publications and source records attributed to M Korobaeff.

At least 19 recordsLinked to original sources
PubMed1996

Bronchial hyperresponsiveness as a predictor of wheezing in a follow-up study of healthy men.

We assessed the relationship between bronchial hyperresponsiveness (BHR) and the onset of wheezing 5 years later, by epidemiological analysis of 194 working men without asthma or wheezing at the first examination. In 1985/ 1986 and 1990/1991, subjects answered a British Medical Research Council questionnaire and performed lung function measurements and methacholine challenge tests (total dose 6 mg). BHR was measured in three ways: (1) FEV1 fall > or = 20% (PD20+); (2) the two-point response slope expressed as percentage decline of FEV1/dose, and (3) a four-parameter model: FEV1 at dose (d)/ prechallenge FEV1 = ONE-k(d-delta)+a, where 'k' is the slope of the relative variation of FEV1 with the dose, 'delta' the threshold dose, and 'alpha' a shape factor. In the 13 new wheezers, the mean values of the two-point slope and of k were significantly increased, and the proportion of reactors was almost threefold (the latter was not statistically significant). Among nonsmokers, delta was significantly lower in new wheezers than in the others, whereas the slope and k had similar mean values. Among smokers, new wheezers had increased mean values for the slope and k, and an increased proportion of reactors, whereas delta was not decreased. Thus, BHR was a significant predictor of wheezing, independent of the method of analysis. Moreover, the model distinguished between two components of bronchial response: wheezing was predicted by sensitivity (delta) in nonsmokers, and by reactivity (k) in smokers.

Adult↗
PubMed1995

Peak expiratory flow rate variability in population surveys. Does the number of assessments matter?

We investigated the effect of reducing the number of daily peak expiratory flow (PEF) measurements on (1) the amplitude of PEF variability and (2) the relationships of this amplitude to bronchial reactivity to methacholine. One hundred seventeen workers (mean age = 38.7 years +/- 9.5; men = 86.3%) recorded their highest of three PEF measurements, every 3 waking hours, ie, 5 times a day, for 7 days, each using a newly purchased peak flowmeter (Vitalograph), and underwent methacholine challenge tests. The variability of PEF of each subject was expressed using the three sets of indices: amp%mean, ie, highest of the daily measurements considered minus the lowest/mean x 100, averaged over 6 days from the second to the seventh, amp%highest (same as amp%mean, but with the highest daily measurements as denominators) and SD%mean (calculated initially as single measures using the data of the 6 days considered, with standard deviation (SD) of each subject's PEF measurements). For each set, we used the indices constructed with the five daily measurements of each day (gold standard), with the first, third, fourth, and fifth, the first, third, and fourth, the first and third, and the first and fourth. The PEF variability was significantly reduced when reducing the number of daily measurements, only when the amp%mean and the amp%highest sets were used. No decrease was observed with the SD%mean set of indices, and SD%mean constructed with the first, third, fourth, and fifth daily measurement was satisfactory. Whatever the sort of index used, three daily measurements were sufficient to identify the group of subjects with excessive variability in relation to methacholine reactivity.

Adult↗
PubMed1995

Misuse of pressurized metered dose inhalers by asthmatic patients treated in French private practice.

Although metered dose inhalers (MDIs) are widely used to treat asthma, clinical studies suggest that misuse is frequent. We studied the frequency of, and factors related to, misuse of MDIs in asthmatic patients of French private practice. 264 chest specialists or general practitioners completed questionnaires including characteristics of patients and asthma, technique in using inhalers and previous instruction, for three consecutive asthmatics aged > 6 years and currently using MDIs: 668 adults (mean age 47.8 years +/- 18.5, 51.8% males) and 100 children (mean age 11.5 years +/- 2.1, 72.0% males) were included. Adequate technique (deep inspiration synchronized with inhaler activation, followed by holding breath for 5 seconds) was used by 33.2% of adults and 26.0% of children; optimal technique (same, plus shaking the inhaler before use and activating it only once) was used by 22.1% of adults and 20.0% of children. The main factor related to misuse of MDIs was absence of previous instruction. However only 26.5% of instructed adults and 22.1% of instructed children used the optimal technique. Misuse of MDIs is a public health problem and instruction is unlikely to solve it. The use of different types of devices, like dry powder breath-actuated inhalers should be encouraged.

Adolescent↗
PubMed1994

HIV infection and tuberculosis: an epidemiological study from a French register.

SETTING: The possible impact of the human immunodeficiency virus (HIV) infection on the epidemiology of tuberculosis has never been studied in a general French population. OBJECTIVE: To describe the evolution of tuberculosis incidence from 1983 to 1991 in a French district (Rhône) and to assess its relationships to HIV-related factors, and to determine the prevalence of HIV infection among adult tuberculosis patients registered from 1989 to 1991. DESIGN: Information on sex, age, country of birth and the history and site of tuberculosis was derived from notification forms, and information on HIV testing was collected especially for this study. RESULTS: During these nine years, 2916 tuberculosis cases were registered. The incidence increased in 1991 after a slow decline in previous years. An analysis of the evolution in the distribution of cases did not suggest any effect of HIV infection on the epidemiology of tuberculosis, with the exception of an increase in the proportion of patients originating from the Antilles and sub-Saharan Africa. The conservative estimate of prevalence of HIV infection was 9.8% in young adult patients. CONCLUSION: The overlap between the population with HIV infection and that with tuberculosis seems to be small and restricted to particularly vulnerable sub-groups of the population of this region.

AIDS-Related Opportunistic Infections↗
PubMed1994

Respiratory symptoms and bronchial reactivity among pig and dairy farmers.

OBJECTIVES: This study assessed the prevalence of respiratory manifestations among French pig and dairy farmers and determined the relationship between bronchial reactivity and respiratory manifestations. METHODS: The pig farmers included 102 men working more than half-time inside swine confinement buildings. There were 51 male dairy farmers and 81 male referents. The demographic characteristics of the three groups were similar except for more smokers among the referents. Each subject completed a standardized questionnaire. Pulmonary function tests were performed before and after a methacholine challenge (cumulative doses 80, 240, and 560 micrograms). Airborne dust, ammonia, and carbon dioxide were measured inside 28 swine confinement buildings. RESULTS: The pig farmers were exposed to a total dust level of 2.41 mg.m-3. The respirable particle concentration was low. The pig and dairy farmers had a significantly higher prevalence of cough and morning phlegm than the referents. Before the methacholine challenge, the dairy farmers had nonsignificantly lower mean lung function values than the other groups. Among the subjects with no history of asthma, nonspecific bronchial hyperreactivity was significantly higher among the pig and dairy farmers than among the referents. There was a fall in the forced expiratory volume in 1 s (FEV 1.0) that was greater than 10% in 6.7% of the referents, 17.9% of the swine workers, and 35.6% of the dairy farmers. This result was unchanged after adjustment for the initial FEV1.0. CONCLUSIONS: The prevalence of respiratory symptoms was significantly higher among the pig farmers without base-line lung function impairment. However, both the pig and the dairy farmers had increased bronchial reactivity.

Adult↗
PubMed1992

Peak expiratory flow variability and bronchial responsiveness to methacholine. An epidemiologic study in 117 workers.

We studied the relationships between peak expiratory flow (PEF) variability and bronchial responsiveness to methacholine in 117 workers attending the annual compulsory examination (mean age, 38.7 yr +/- 9.5; men, 86.3%). Subjects recorded their highest PEF out of three, every 3 waking hours (i.e., five times a day) for 7 days, each using a newly purchased Vitalograph peak flow meter, and underwent methacholine challenge tests with a maximal cumulative dose of 1,200 micrograms. Those with a FEV1 fall of 15% or more were considered as reactors. The variability of PEF was expressed as the amplitude percent mean, calculated from daily amplitude (highest-lowest reading/mean reading of the day x 100), averaged over 6 days, from the second to the seventh. This index had a continuous distribution, skewed towards the greatest amplitudes, and correlated negatively with FEV1 (r = -0.25, p = 0.01). Subjects with asthma (n = 8) had greater variations. In the 109 nonasthmatics, greater variability was observed in subjects with wheeze apart from colds, breathlessness, or hay fever; the average amplitude was greater in reactors than in nonreactors to methacholine (16.9% versus 9.3%, p less than 0.001). The subjects with excessive PEF variability were all methacholine reactors, but they were only a subgroup of the reactors. These results provide evidence that excessive PEF variability is an indicator of bronchial hyperresponsiveness to methacholine in a population sample.

Adult↗
PubMed1992

Frequency and correlates of the saw-tooth pattern of flow-volume curves in an epidemiological survey.

The object of this report was to assess the possibility of identifying saw-tooth patterns on flow-volume curves in men aged 28 to 58 years. We studied the frequency of these patterns and their relationships with two indirect signs of UAO increase in FEV1/PEF and FEF50%/FIF50% ratios--as well as with clinical and functional data. Twenty-six of the 360 subjects surveyed, ie, 7.2 percent, had flow oscillations in the inspiratory and/or expiratory part of flow-volume curves, corresponding to the definition of the saw-tooth pattern. We observed significant relationships between the saw-tooth pattern and the mean FEV1/PEF ratio. In 97 subjects, the proportion of those with saw-tooth patterns was 13.4 percent, and the mean FEF50%/FIF50% ratio was 1.53 in those with the pattern vs 1.07 in those without it. These results show that the saw-tooth pattern was not rare in these men.

Adult↗
PubMed1992

Relationship of upper airways disorders to FEV1 and bronchial hyperresponsiveness in an epidemiological study.

Associations of upper airways disorders (UAD) with forced expiratory volume in one second (FEV1) and bronchial methacholine response were studied, taking smoking habits into account. We used epidemiological data drawn from a population of 324 men, aged 27-58 yrs. Lower FEV1 level was related to hay fever (p = 0.01), usual (p = 0.01) and chronic (p = 0.02) rhinitis and common cold on the day of examination (p = 0.04). Allowance for the major potential confounding factor, tobacco smoking, showed similar results. Bronchial methacholine response was heightened in men reporting hay fever compared to those without (p = 0.01) but also in men reporting chronic rhinitis (p = 0.06), a group which did not exhibit skin prick test positivity more often than other subjects. Exclusion of asthmatics and taking into account smoking and skin prick test positivity yielded mostly similar results. Our data support the hypothesis of an association between lung impairment, as assessed by lower FEV1 and bronchial hyperresponsiveness to methacholine, and different types of UAD, allergic or not.

Adult↗
PubMed1991

Blood eosinophilia and FEV1. Cross-sectional and longitudinal analyses.

A previous cross-sectional analysis of 1980 data from a population of working men in the Paris area has shown a significant relationship of blood eosinophilia to a reduced FEV1 among nonsmokers, remaining after excluding men with a history of asthma. In the present report, we reexamine this relationship, after taking into account asthma, bronchial hyperresponsiveness, and positive skin prick tests, using data collected in 1985 in a subsample of 363 men from the initial population. Blood eosinophilia, defined by 5% or more eosinophils or by 250 or more eosinophils per cubic millimeter appeared to be associated with a lower FEV1, primarily in nonsmokers. A difference of approximately 0.40 L was observed in never-smokers with eosinophilia (greater than or equal to 5% of eosinophils) compared with those without. This association persisted after exclusion of subjects with atopy, asthma, and bronchial hyperresponsiveness. Longitudinally, no significant association was observed between 1980 eosinophilia and the annual FEV1 decline between 1980 and 1985, even in nonsmokers. The results of our cross-sectional analyses suggest that asthma or asthma-like disorder does not explain the association between eosinophilia and FEV1. The role of eosinophil in respiratory disorders may go beyond its intervention in allergy. Further longitudinal studies are needed to better understand discrepancies between cross-sectional and longitudinal data and whether eosinophilia is a risk factor for chronic air-flow limitation.

Adult↗
PubMed1988

Relation of perceived nasal and bronchial hyperresponsiveness to FEV1, basophil counts, and methacholine response.

Perceived nasal and bronchial hyperresponsiveness to tobacco smoke and cold air were assessed in 912 working men in the Paris area. Baseline lung function measurements and peripheral leucocyte counts with standard differential counts were performed. At least one perceived nasal or bronchial hyperresponsiveness symptom was reported by 15.7%. Current smoking was significantly less frequent among those with cough induced by tobacco smoke. Rhinitis induced by cold air was associated with lower FEV1 (p less than 0.01) and the association remained after adjustment for smoking, asthma, and wheezing (p = 0.06). Symptoms induced by cold air were related to circulating basophils. Neither perceived nasal nor perceived bronchial hyperresponsiveness was significantly related to the airway response to methacholine in a sample of the group (n = 324) surveyed again five years later. The result suggest that the symptom of rhinitis provoked by cold air is a possible "new" risk factor or marker for chronic airflow limitation.

Adult↗
PubMed1987

Variation of lung function during the workshift among cotton and jute workers.

Cotton and jute dust exposure is known to induce reversible airway obstruction. We compared 50 exposed workers to 99 non exposed workers for the prevalence of respiratory symptoms and ventilatory impairment, and for variations in pulmonary function after five working days and after inhalation of salbutamol. The prevalence of respiratory symptoms was not significantly different between the two groups. Pulmonary function was not different on Monday morning, however, significant differences were observed on Friday afternoon. The exposed workers had a lower flow rate at 75% of exhaled forced vital capacity than controls (P less than 0.01). Salbutamol induced greater bronchodilatation in the exposed group. Comparison with a control group is necessary to take into account the change in pulmonary function. Repeated tests, combined with pharmacological tests, are able to differentiate the lung function pattern of exposed and non exposed workers.

Adult↗
PubMed1986

Eosinophils, smoking, and lung function. An epidemiologic survey among 912 working men.

The relationship of eosinophilia with smoking habits and with baseline lung function measurements has been studied in a working population of 912 men in the Paris area. Absolute numbers of eosinophils were related significantly to a history of asthma and eczema in childhood as well as to current tobacco consumption, whereas the percentage of eosinophils was related only to the occurrence of asthma and eczema. Forced expiratory volume in one second adjusted for smoking was significantly related to asthma, the presence of a common cold on the day of examination among those with a history of wheezing, and the percentage of eosinophils. The association between FEV and eosinophils was restricted to never smokers. Among never smokers without a history of asthma, eczema, wheezing, or a common cold on the day of examination, eosinophil percentages and counts were significantly associated with the level of FEV; eosinophil percentages explained 4.4% of the variance of FEV. These results suggest that eosinophilia might be a risk factor for chronic air-flow limitation among adult nonsmokers.

Adult↗
PubMed1985

Common cold with cough on the day of examination: a factor that should be taken into account in epidemiological studies on pulmonary function.

Epidemiologists using pulmonary function tests agree that a number of factors have to be taken into account. In a study carried out among 912 men aged 22 to 54 we found that those having a common cold and cough on the day of examination had lower pulmonary function values. So we suggest that these symptoms should also be considered as a potential confounding factor.

Adult↗
PubMed1984

[Comparative statistical study of global and local functional respiratory data in 2 groups of patients with pulmonary or pleural tuberculosis].

Two groups of patients with unilateral tuberculosis, either pulmonary (36 cases) or pleural (75 cases) were studied. The clinical and functional results were compared statistically. These two groups were similar in terms of age, sex, tobacco consumption, the radiological unilaterality of their disease and the global reduction of respiratory function (assessed by VC, FEV1, TPC and TLCO), which can be considered to be essentially due to the local disease. In both groups, the radiological image (extent of the lesion, shape of the lesion) is the only clinical factor statistically related to the functional values. The two groups differ in terms of two functional parameters which reflect different pathophysiological mechanisms in the affected lung. The group with pulmonary tuberculosis presents an obstructive ventilatory syndrome (reduction of the FEV1/VC ratio and increase in the RV/TPC ratio), which reflects the bronchial involvement in the disease. The group with pleural tuberculosis presents a pulmonary distention (increased RV/TPC ratio), which is related to disturbed transmission of the pleural pressure to ventilated alveolar zones. Secondly, in the group with pulmonary tuberculosis, the ventilation and perfusion deficits are equivalent, while in the pleural tuberculosis group, the ventilatory deficit is predominant. Thus the global reduction in ventilatory function which is the same in the two group is caused by fundamentally distinct pathophysiological mechanisms in the two groups of patients.

Adult↗